The bacterium, Enterobacter aerogenes NBO2 was cultivated in 250 ml Erlenmeyer flask under submerged fermentation and physiochemical characteristics were studied in order to improve the pectinase production. Fermentation condition improved were pH 6.5, cultivation temperature of 37°C, inoculums size of 3% (v/v) 7.4x10 8 cell/ml and agitation speed of 250 rpm, together with pectin concentration of 1.50% (w/v) and 0.26% of yeast extract as carbon and nitrogen sources, respectively had produced the highest pectinase production of about 18.54 U/mL and 0.43 g/L cell growth at 24 hours incubation time. The enzyme production by this bacterial isolate was found not growth dependent. There were increment in enzyme production and cell growth after improvement of physical and chemical parameters.

The evolving trend to use larger transgenes and their associated increased chance of unexpected genetic events mandates more careful characterization of transgenic mice. In characterizing our five new mouse strains transgenic for the BAC, bEMS4, we have identified the highest copy number reported to date: the stable incorporation of approximately 40 copies of a 194-kb expressed transgene in a single insertion site. We caution, however, that standard molecular techniques failed to identify a balanced translocation in another strain, and an inappropriate site of insertion in a third. Molecular cytogenetic analysis using metaphase FISH was the minimum level of characterization needed to reveal these unexpected genetic events. In addition, we combined FISH and SKY to identify the transgene at the breakpoints of the balanced translocation, t(3;9). This is the first description of a BAC-mediated chromosomal rearrangement and the first application of SKY to identify transgene-induced chromosomal rearrangements.

Bacterial cells of Enterobacter aerogenes NBO2 were entrapped in calcium alginate beads in order to enhance polygalacturonase production compared to free cells. The optimized condition of 5 % (w/v) sodium alginate concentration, agitation speed of 250 rpm, and 15 beads of calcium alginate with inoculum size of 4 % (v/v; 5.4 × 10(7) cells/ml) produced 23.48 U/mL of polygalacturonase compared to free cells of 18.54 U/ml. There was about 26.6 % increment in polygalaturonase production. However, in this study, there was 296.6 % of increment in polygalacturonase production after improvement parameters compared to before improvement parameters of calcium alginate bead immobilization cells (5.92 U/ml). This research has indicated that optimized physical parameters of calcium alginate bead immobilization cells have significantly enhanced the production of polygalacturonase.

No abstract